INTRODUCTION. 11 



ceous ground-beetles (Carabidce), the diving beetles (Bijt.iscidcB), the 

 lady-birds (Coccinelladce), and some others, are eminently serviceable 

 by preying upon caterpillars, plant-lice, and other noxious or destruc- 

 tive insects. The water-lovers (Hydrophilidce), rove-beetles (Staphy- 

 linidcc), carrion-beetles (Silphadce), skin-beetles (Bermesladce, Bijr- 

 rhidcs, and Trogida), bone-beetles (some of the Nitidulada and Cle- 

 ridce), and various kinds of dung-beetles (Sphceridiadce, Histerida, 

 Geotrvpida* , Coprididcc*, and Ap/wdiadce*), and clocks (Pimeliada 

 and BlaptidcE), act the useful part of scavengers, by removing car- 

 rion, dung, and other filth, upon which alone they and their larvae 

 subsist. Many Coleoptera (some Sfaphylinidce and Nitididadce, Bia- 

 perididce, some Serropalpidce, Mycetophagidce, Erotylida, and En- 

 domychida) live altogether on agarics, mushrooms, and toadstools, 

 plants of very little use to man, many of them poisonous, and in a 

 state of decay often offensive ; these fungus-eaters are therefore to 

 be reckoned among our friends. There are others, such as the stag- 

 beetles (Lucanidce), some spring-beetles (Elaterida), darkling beetles 

 (Tenebrionidce), and many bark-beetles (Helopidce, CisteladcE, Serro- 

 palpidce, (Edemeradcn, Cucujada, and some Trogositadce), which, liv- 

 ing under the bark and in the trunks and roots of old trees, though 

 they may occasionally prove injurious, must, on the whole, be consid- 

 ered as serviceable, by contributing to destroy, and reduce to dust, 

 plants that have passed their prime, and are fast going to decay. And, 

 lastly, the blistering-beetles (Cantharididce.) have, for a long time, 

 been employed with great benefit in the healing art. 



2. — Orthoptera [Cockroaches, Crickets, Grasshoppers, 

 &fc). Insects with jaws, two rather thick and opake upper 

 wings, overlapping a little on the back, and two larger, thin 

 wings, which are folded in plaits, like a fan. Transformation 

 partial. Larva? and pupa? active, but wanting wings. 



All of the insects of this order, except the camel-crickets (Manti- 

 dce), which prey on other insects, are injurious to our household pos- 

 sessions, or destructive to vegetation. 



3. — Hemiptera (Bugs, Locusts, Plant-lice, &fc). Insects 

 with a horny beak for suction, four wings, whereof the up- 

 permost are generally thick at the base, with thinner extremi- 



* All the Scarabaeidae of my Catalogue, from Ateuchus to Geotrupes inclusive, 

 to which may be added many included in the genus Scarabceus. 



